NEW YORK (Reuters Health) - At long-term follow-up, nearly two thirds of children who undergo liver transplantation will have chronic hepatitis, a condition that raises the risk of progressive fibrosis and cirrhosis, according to a report in the May issue of Hepatology.

The bad news is that standard measurement of liver function, such as AST and ALT levels, are not useful in detecting chronic hepatitis or monitoring the progress of the allograft. Instead, regular measurement of autoantibodies may be needed, lead author Dr. Helen M. Evans, from Birmingham Children's Hospital in the UK, and colleagues note.

The findings are based on an analysis of serial liver biopsies in 158 asymptomatic children with 5-year survival of their liver allograft. The histology results were then correlated with clinical, serological, and biochemical findings. Cyclosporine A was the main immunosuppressive agent used and corticosteroid withdrawal began 3 months after transplantation.

At 1-year follow-up, 68% of subjects had normal liver histology, but by 10 years, the percentage had fallen to 31%. During this time, the rate of chronic hepatitis, the most common histologic abnormality, increased from 22% to 64%.

Chronic hepatitis-associated fibrosis rates rose from 52% to 91% during the 10 years of follow-up. Moreover, the severity of fibrosis increased with time: 15% of cases had progressed to cirrhosis by 10 years.

As suggested, levels of AST and ALT were only slightly elevated in patients with chronic hepatitis and were not useful in identifying the condition. By contrast, autoantibody positivity was much more common in children with hepatitis than in those with normal histology: 80% vs. 10% at 10 years.

Autoimmune hepatitis was diagnosed in four children and another two tested positive for infection with hepatitis C virus. The cause of hepatitis in the remaining cases was unknown.

The results "indicate that important histologic abnormalities can be seen in protocol biopsies obtained from children who are clinically well with good graft function and normal liver biochemistry," the researchers conclude.